JPS58169812A - Superconductive insulated wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a superconducting insulated wire in which heat transfer characteristics are improved by providing a specific insulating coating on the superconducting wire.

[Technical background of the invention and its problems] Conventionally, methods for improving the heat transfer characteristics of superconducting wires include mechanically applying knurling, cross processing, bit processing, fin processing, etc. to superconducting wires. Providing unevenness on the surface, electrolytically polishing (anodizing) the superconducting wire, ■ Bonol C
There is a method of increasing the surface area by applying chemical surface treatments such as surface treatment and Blackie treatment.

However, the former method of mechanically creating unevenness requires the stabilizing base material to be thicker, and has the disadvantage of significantly increasing production costs, while the latter chemical method is a 21st method. Although this method is quite effective, it has the disadvantage that it is necessary to perform an IG treatment for about 1 inch to perform surface treatment.

In addition, the latter method, electrolytic polishing, does not show much improvement in cooling properties, and ■Bonol C treatment and 1Ratsky treatment form needle-like products on the surface, which improve cooling properties, but W# It also had the disadvantage of being extremely weak against scratches.

The inventors of the present invention have carried out intensive research to eliminate the above-mentioned drawbacks, and have found that by applying a specific insulating paint to a superconducting wire and baking it, the resulting coating film is porous, which improves the heat transfer characteristics of the superconducting wire. In addition, the coating film is stronger than the above-mentioned nail-like product and can withstand high-temperature heat treatment, making the superconducting wire useful as an insulated wire and free from stickiness.

[Object of the Invention] The present invention was made based on such knowledge, and an object of the present invention is to provide a superconducting insulated wire with improved heat transfer characteristics.

1. Outline of the Invention] The superconducting insulated wire of the present invention is characterized in that a coated and baked layer of an insulating paint containing polyborosiloxane resin as a main component is provided on the metal surface of the outer periphery of the superconducting wire.

The superconducting wire used in the present invention includes alloy superconducting wires such as Nb-11, Nb ssn , VsGa, Nb5Aβ
There are compound superconducting wires such as

The insulating paint used in the present invention is, for example, a polyborosiloxane resin mixed with a silicone resin and an inorganic filler, and then mixed with cresol, methyl-2-pyrrolidone (
Some are obtained by dissolving or dispersing them in organic solvents such as NMP). This insulating paint has a porous coating after baking and can withstand long-term heat treatment at high temperatures.

Note that the polyborosiloxane resin is (a) Si X < , Si RX3, Si RR'
A silane compound represented by X2 (in the above formula, R, R'
is an alkyl group or an aryl group; Si
The atomic ratio of diboron is 1 = 10 to 10:1, preferably 5
:1 to 1:5 by heating at 50 to 800'C to conduct condensation polymerization.

At this time, organic solvents such as acetylacetone, acetic anhydride, cresol, tetrahydronolane, xylene, NMP, and dimethylacetamide may be used as necessary.

However, by blending and reacting the following components with the components (a) and (b) above, the flexibility and water resistance of the resulting polyborosiloxane resin can be improved.

(C) Silicone oils such as methylphenyl silicone oil and dimethyl silicone oil (d) Aromatic alcohols, aliphatic polyhydric alcohols, phenols, aromatic carboxylic acids (e) Lead, manganese, balt, zinc, calcium, etc. (f) a mixture of organic salts of triethanolamine, monoethanolamine,
The blending amounts of nitrogen-containing compounds (C) to (f) such as jetanolamine, phenylenediamine, ethylenediamine, and trimethylenediamine are the same as those for components (a) and (b).
), component (C) is 5 to 100 parts by weight, component (d> is 5 to 30 parts by weight, (
e) component is 0.05 to 10 parts, (f) component is:
It is desirable that the number of N atoms be 5 to 200 per 100 boron atoms in component (b). Above (C
) to (f) may be used alone or in combination of two or more.

In the present invention, commercially available silicone resins can be used as the silicone resin compounded in the insulating paint. For example, T
There is SR116. In addition to pure silicone, there are silicone alkyds, silicone polyesters, silicone epoxies, and the like.

The suitable amount of this compound is 5 to 400 parts, preferably 10 to 200 parts per 100 parts of Kirin resin. If it is less than this range, the stability will be poor, and if it exceeds this value, the heat resistance will be poor.

Furthermore, examples of the inorganic filler include mica, talc, aluminum oxide, zirconium oxide, magnesium oxide, tungsten, aluminum silicate, magnesium silicate, and ceramic frit prepared by mixing and dissolving several metal oxides. These may be used alone or in combination to obtain the same effect. These inorganic fillers may be natural or synthetic, but are preferably fine powders with a particle size of 10 μm or less. The amount of this compound is 5 to 300, preferably 5 to 200, per 100 parts by weight of the polyborosiloxane resin and silicone resin.
Heavy parts are suitable. If it is less than this value, the heat resistance will be poor, and if it exceeds this value, the mechanical properties will be deteriorated.

In the present invention, for example, the production of a compound-based superconducting insulated wire is preferably carried out by the following method because Nb5S11 and the like produced by heat treatment are brittle.

That is, the compound-based superconducting wire is shaped into a final shape and then baked into a cloth. The resulting coating film can withstand heat treatment at a temperature of 500° C. or higher for a long period of time.

Next, this is wound into a bundle or a bobbin to give 550 to 80
After heat treatment at 0°C for 20 to 200 hours, Nb ss
Compounds such as n 1VsGa and Nb sAl are formed. Note that if a superconducting wire whose surface is coated with a non-magnetic material such as silver plating is used during coating and baking, the adhesion and pressure resistance of the coating film will be further improved.

In addition, alloy-based superconducting insulated wires are produced by, for example, drawing Nb-Ti superconducting wires and then heat-treating or annealing them to obtain α-11
It is obtained by precipitating, cold working, and then baking an insulating paint.

“Embodiments of the invention”′]“゛ Next, examples of the present invention will be described.

(Manufacture of insulating paint) 432 g (2 moles) of diphenyldihydroxysilane,
Boric acid 83(](11,3 mol, viscosity (25℃) is 10
Centistokes dimethyl silicone oil 2569
into a flask and stirred in a nitrogen atmosphere from room temperature for 4 hours.
The temperature was raised to QO°C over 6 hours, and the mixture was further heated and stirred at 400°C for 1 hour to carry out a polycondensation reaction. During the reaction process, 66 g of water and 709 unreacted low molecular weight silicone oil were distilled off.

The polyborosiloxane resin thus obtained was colorless and solid at room temperature, and the yield was 525 gC. The number average molecular weight of this resin was 1500 when converted to polystyrene, and the residual rate after firing up to 700°C was 35%. This was dissolved in NMP to obtain a resin solution with a nonvolatile content of 45.6%.

333 g of this polyborosiloxane resin solution was added to silicone resin (TSR116 manufactured by Toshiba Silicone Co., Ltd.) 30 (1, I
Magnesium t-chloride 120! + together with NMP3000
An insulating paint was produced by dissolving it in

Example 1 295 Nb3Sn multi-wire rods 1111 thick x 2'1
After processing it into a rectangular shape with a width of m, it was immediately plated with 2 μm of silver, and then coated with the above-mentioned insulating paint at 450° C. to obtain a wire rod of 0 μm. Even when this wire was bent to a bending diameter of 3 nφ, no defects occurred in the coating. This 2000m wire has a body diameter of 800m.
Wound around nφ stainless steel bobbin and heated to 72°C at 700°C.
When heat treatment was performed in an argon gas atmosphere for several hours, there was no adhesion between the wires over the entire length.

The dielectric breakdown voltage of the superconducting insulated wire thus obtained was 400V. In addition, the heat transfer properties of this material were approximately 10% higher in recovery heat flow rate than the same wire material whose surface was treated with Evonol C.

Example 2 After applying the above-mentioned insulating paint to a NbT1 fine multi-wire having a three-layer structure with an outer diameter of 1.6uφ, it was heated to 300°C.
Final annealing was carried out for 2 hours. Under these conditions, the above-mentioned insulating paint was cured to form a porous coating as shown in the micrograph of the drawing.

Twisting 17 of these wires 1!3.0mmX 14.0m+
Compression molded strands of + dimension were produced.

The coating film of the superconducting insulated wire obtained by molding in this manner was maintained in a sufficiently firm state. Furthermore, regarding the heat transfer characteristics of this material, a value about 10% higher in recovery heat flow rate was obtained compared to the same wire material whose surface was treated with Evonol C.

[Effects of the Invention] From the above examples, by providing a coating and baking layer of an insulating paint containing polyborosiloxane resin as a main component on the outer periphery of the superconducting wire, heat transfer characteristics can be improved and sticking during heat treatment can be prevented. A separator is no longer required, and the coating film maintains a predetermined dielectric breakdown voltage after heat treatment.

Further, the superconducting insulated wire of the present invention is particularly suitable as a wire for a magnet that is constantly exposed to a pulsed magnetic field, such as a pulsed magnet.

[Brief explanation of drawings]

The figures are microscopic photographs of the surface of the superconducting insulated wire of the present invention, (a) magnified by 50 and (b) magnified by 3504B. Representative Patent Attorney Sasa Suyama = (1 other person) 1'. (×50) (×50) Continued from page 1 0 Author: Kozo Arahara Inside Showa Cable Electric Co., Ltd., 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City 0 Author: Tetsuo Hoshino Oda Sakae, Kawasaki-ku, Kawasaki City 2-1-1 Showa Electric Wire and Cable Co., Ltd. Internal Procedures Amendment (Method) % Formula % 1 Incident Display Showa 57 1lIIIIII No. 53272 No. 2
, Title of the invention: Superconducting insulated wire 3, Relationship with the case of the person making the amendment: Patent applicant 4, agent 7, page 10, line 20 to page 11, line 2 of the specification subject to amendment are corrected as follows. [The figures are micrographs showing the particle structure of the surface of the superconducting insulation resistance stitch of the present invention. (1) is 50x, (b) is 350x
It's double. ”

Claims (1)

[Claims] A superconducting insulated wire characterized in that a coated and baked layer of an insulating paint containing polyborosiloxane resin as a main component is provided on the metal surface of the outer periphery of the superconducting wire.